1. Field of the Invention
The present invention relates to a high frequency power amplifier for switching the routes in an amplifier according to output powers.
2. Background Art
A high frequency power amplifier operating in a high-frequency band of several tens of megahertz is used in mobile telephones and mobile terminals. In this high frequency power amplifier, the route in the amplifier is switched each time for obtaining the high power output of 28.25 dBm, the middle power output of 17 dBm, and the low power output of 7 dBm. Thereby, the operation efficiency at each output power can be improved (for example, refer to “Proceedings of the 36th European Microwave Conference”, P. 348-P. 351).
In conventional high frequency power amplifiers, in common routes when low and middle power outputs are obtained, impedance matching has been performed by a switching element and a capacitor connected in parallel.